ICU · Infectious diseases
Acute severe community-acquired pneumonia: ICU pathway, empiric therapy, and complications
Also known as Severe CAP · ICU pneumonia · Empiric pneumonia therapy · IDSA ATS CAP · Pneumonia complications
Severe community-acquired pneumonia in the ICU — IDSA/ATS severe-CAP criteria, CURB-65/PSI/SMART-COP, time to antibiotics (Seymour, Kumar), ATS/IDSA 2019 empiric regimens with MRSA and Pseudomonas widening, the 2023 ERS/ESICM/ESCMID/ALAT sCAP guideline (macrolide over fluoroquinolone, HFNO, procalcitonin, oseltamivir, corticosteroids if shock), the 2025 ATS update (corticosteroids suggested in severe CAP excluding influenza; 5 or more days of antibiotics), the corticosteroid trials (CAPE COD, Torres, Blum, Siemieniuk) and lung-protective ventilation.
Checked against its sources on 8 Oct 2026
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Red flags
- Septic shock needing vasopressors or respiratory failure needing ventilation = severe CAP — admit directly to ICU
- Each hour of antibiotic delay was associated with higher mortality (Seymour OR 1.04 per hour; Kumar 7.6% fall in survival per hour in septic shock)
- Prior respiratory isolation of MRSA or Pseudomonas, or recent hospitalisation with IV antibiotics, mandates widened empiric cover with cultures
- Influenza-positive inpatients get oseltamivir regardless of illness duration — and standard antibacterial therapy
- 2025 ATS: suggest systemic corticosteroids in severe CAP, excluding influenza pneumonia
Meet the patient
A 67-year-old man with COPD presents with 3 days of fever and productive cough. He is confused, RR 34, SpO2 88 per cent on air, BP 82/48 after 2 L of crystalloid and needs noradrenaline; the chest film shows right lower and middle lobe consolidation. He meets a major criterion — septic shock needing vasopressors — so this is severe CAP and he goes directly to ICU.[1]
Three decisions shape his first day: how fast the antibiotic goes in, whether his risk factors demand MRSA or Pseudomonas cover, and whether he gets hydrocortisone.[4][1][2]
References21ShowHide
- [1]Metlay JP, Waterer GW, Long AC, et al. Diagnosis and Treatment of Adults with Community-acquired Pneumonia. An Official Clinical Practice Guideline of the American Thoracic Society and Infectious Diseases Society of America. American journal of respiratory and critical care medicine, 2019.PMID 31573350
- [2]Jones BE, Ramirez JA, Oren E, et al. Diagnosis and Management of Community-acquired Pneumonia: An Official American Thoracic Society Clinical Practice Guideline. American journal of respiratory and critical care medicine, 2026.PMID 40679934
- [3]Martin-Loeches I, Torres A, Nagavci B, et al. ERS/ESICM/ESCMID/ALAT guidelines for the management of severe community-acquired pneumonia. Intensive care medicine, 2023.PMID 37012484
- [4]Seymour CW, Gesten F, Prescott HC, et al. Time to Treatment and Mortality during Mandated Emergency Care for Sepsis. The New England journal of medicine, 2017.PMID 28528569
- [5]Kumar A, Roberts D, Wood KE, et al. Duration of hypotension before initiation of effective antimicrobial therapy is the critical determinant of survival in human septic shock. Critical care medicine, 2006.PMID 16625125
- [6]Bouadma L, Luyt CE, Tubach F, et al. Use of procalcitonin to reduce patients' exposure to antibiotics in intensive care units (PRORATA trial): a multicentre randomised controlled trial. Lancet (London, England), 2010.PMID 20097417
- [7]Lim WS, van der Eerden MM, Laing R, et al. Defining community acquired pneumonia severity on presentation to hospital: an international derivation and validation study. Thorax, 2003.PMID 12728155
- [8]Fine MJ, Auble TE, Yealy DM, et al. A prediction rule to identify low-risk patients with community-acquired pneumonia. The New England journal of medicine, 1997.PMID 8995086
- [9]Charles PG, Wolfe R, Whitby M, et al. SMART-COP: a tool for predicting the need for intensive respiratory or vasopressor support in community-acquired pneumonia. Clinical infectious diseases : an official publication of the Infectious Diseases Society of America, 2008.PMID 18558884
- [10]Siemieniuk RA, Meade MO, Alonso-Coello P, et al. Corticosteroid Therapy for Patients Hospitalized With Community-Acquired Pneumonia: A Systematic Review and Meta-analysis. Annals of internal medicine, 2015.PMID 26258555
- [11]Torres A, Sibila O, Ferrer M, et al. Effect of corticosteroids on treatment failure among hospitalized patients with severe community-acquired pneumonia and high inflammatory response: a randomized clinical trial. JAMA, 2015.PMID 25688779
- [12]Confalonieri M, Urbino R, Potena A, et al. Hydrocortisone infusion for severe community-acquired pneumonia: a preliminary randomized study. American journal of respiratory and critical care medicine, 2005.PMID 15557131
- [13]Blum CA, Nigro N, Briel M, et al. Adjunct prednisone therapy for patients with community-acquired pneumonia: a multicentre, double-blind, randomised, placebo-controlled trial. Lancet (London, England), 2015.PMID 25608756
- [14]Dequin PF, Meziani F, Quenot JP, et al. Hydrocortisone in Severe Community-Acquired Pneumonia. The New England journal of medicine, 2023.PMID 36942789
- [15]Arancibia F, Bauer TT, Ewig S, et al. Community-acquired pneumonia due to gram-negative bacteria and pseudomonas aeruginosa: incidence, risk, and prognosis. Archives of internal medicine, 2002.PMID 12196083
- [16]Amati F, Restrepo MI Emerging Resistance of Gram Negative Pathogens in Community-Acquired Pneumonia. Seminars in respiratory and critical care medicine, 2020.PMID 32629487
- [17]Martin-Loeches I, Garduno A, Povoa P, et al. Choosing antibiotic therapy for severe community-acquired pneumonia. Current opinion in infectious diseases, 2022.PMID 35190510
- [18]Rybak MJ, Le J, Lodise TP, et al. Therapeutic Monitoring of Vancomycin for Serious Methicillin-resistant Staphylococcus aureus Infections: A Revised Consensus Guideline and Review by the American Society of Health-system Pharmacists, the Infectious Diseases Society of America, the Pediatric Infectious Diseases Society, and the Society of Infectious Diseases Pharmacists. Clinical infectious diseases : an official publication of the Infectious Diseases Society of America, 2020.PMID 32658968
- [19]Psallidas I, Corcoran JP, Rahman NM Management of parapneumonic effusions and empyema. Seminars in respiratory and critical care medicine, 2014.PMID 25463162
- [20]Acute Respiratory Distress Syndrome Network, Brower RG, Matthay MA, et al. Ventilation with lower tidal volumes as compared with traditional tidal volumes for acute lung injury and the acute respiratory distress syndrome. The New England journal of medicine, 2000.PMID 10793162
- [21]Mandell LA, Wunderink RG, Anzueto A, et al. Infectious Diseases Society of America/American Thoracic Society consensus guidelines on the management of community-acquired pneumonia in adults. Clinical infectious diseases : an official publication of the Infectious Diseases Society of America, 2007.PMID 17278083